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Opencore 0.7.2 default boot disc changed after booting Win10

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Hi

I have Win10 on a separate SSD and I don't use it very often. I have my Big Sur drive set as default, I set this in system preferences - Start up disk in macOS and after reboot it will use Big Sur as the default boot disk. However, when I occasionally boot Windows 10, it then selects this as the default boot disk (though not in BIOS)

Can anyone point me to a solution?
 
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Hi

I have Win10 on a separate SSD and I don't use it very often. I have my Big Sur drive set as default, I set this in system preferences - Start up disk in macOS and after reboot it will use Big Sur as the default boot disk. However, when I occasionally boot Windows 10, it then selects this as the default boot disk (though not in BIOS)

Can anyone point me to a solution?

The BIOS list defines the boot device order when no other info is available.

But boot device can be controlled by NVRAM too, which makes sense when continuing a system update, etc.

The combinatorials of which device will selected, when devices come-and-go, what bootloader, and which OS under what startup conditions are mind-numbing, so I've never tried to nail it down, but hopefully this gives you a way to think about it when searching for details on your specific HW.

If you post your findings, I'm sure there are others who will want to know.
 
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However, when I occasionally boot Windows 10, it then selects this as the default boot disk (though not in BIOS)
I assume you mean this happens in OpenCore if that's what you're using.
Can anyone point me to a solution?
Disable the fast startup option as described here if you haven't already. It can contribute to this issue.
 
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I assume you mean this happens in OpenCore if that's what you're using.

Disable the fast startup option as described here if you haven't already. It can contribute to this issue.
Hi, yes in OC. Thanks for the tip, I checked the Fast Startup setting in Win10 and it was already disabled. Strangely, I booted into Windows yesterday and then when I restarted OC correctly selected BigSur for boot this time. I will monitor and report back to this thread if I have any info/solution
 
Joined
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Messages
442
Motherboard
Gigabyte Z390 M Gaming
CPU
i5 9400F
Graphics
RX 580
Mac
  1. iMac
Mobile Phone
  1. iOS
The BIOS list defines the boot device order when no other info is available.

But boot device can be controlled by NVRAM too, which makes sense when continuing a system update, etc.

The combinatorials of which device will selected, when devices come-and-go, what bootloader, and which OS under what startup conditions are mind-numbing, so I've never tried to nail it down, but hopefully this gives you a way to think about it when searching for details on your specific HW.

If you post your findings, I'm sure there are others who will want to know.
Thanks, I only ever have my macOS drive selected in BIOS as the one and only boot disk. Problem seems to have disappeared for now, I’ll report back if and when I have any useful info
 
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